The latest version of Gimp in Linux Mint 21.2, is :
Version:2.10.30-1build1
Updates to apps, including gimp, do not come immediately to Linux Mint.
There is quite a bit of research happen first, to ensure that the 'update' will not break anything in the Linux system
Te current stable release from the gimp website is : 2.10.36 (2023-11-05).
Warnings and information
Flatpak build available in: x86-64 and AArch64 (note: i386 and ARM-32 versions used to be published, yet are now stuck at GIMP 2.10.14 and 2.10.22 respectively).
If available, the official package from your Unix-like distribution is the recommended method of installing GIMP!
As @Condobloke mentioned, Mint/Ubuntu are usually a little behind. That isn't bad, because it means they are more thoroughly tested. If you want the "latest and greatest" versions of software, you might want to move to a rolling release like Arch or Fedora,
they tend to update more frequently, but the downside is, they are a little less tested before they are released.
Personally, I'm content with an AppImage of 2.10.25, built into a 'portable' ROX-App directory with its own self-contained config files. It does everything I need from it, so.....why change?
I'm still using 2.8 in some of my 32-bit Pups. Again, it does what I need from it....